Conventionally, a stacked heat exchanger whose flow paths are formed by stacking a plurality of plates formed with a plurality of through holes respectively and communicating the through holes of the respective plates is known. In the following Patent Document 1, one such example of the stacked heat exchanger is shown.
In the heat exchanger disclosed in the following Patent Document 1, the respective stacked plates constituting the heat exchanger are formed with a lot of through holes respectively. The lot of through holes formed in the respective plates include elongated holes extending linearly, elongated holes bent at a right angle, and elongated holes bent in a dogleg shape, or the like. The lot of through holes formed in the respective plates are arranged so as to line up along a predetermined direction respectively, and the arrangement directions of the through holes in the two plates stacked to each other are directions corresponding to each other. Then, the through holes formed in the two stacked plates are communicated to each other in their arrangement directions, thereby flow paths that allow a fluid as an object of heat exchange to flow are formed.
However, in the conventional heat exchanger, a plurality of through holes having different shapes are formed in the respective plates, and those through holes are formed in a state that different arrangement patterns are intermingled, therefore there is a problem that the internal structure of the heat exchanger is complicated and the production cost of the heat exchanger increases.